Natural disasters, particularly fires or earthquakes, can cause substantial injuries to humans. For disasters occurring in high-rise buildings, life-saving equipment for use require the highest effectiveness and safety due to their special application, environment of use and shelf life. However, because conventional life-saving equipment used for high building rescues contain ineffective structures, personnel have difficulties in rescuing people from the high buildings during fire. This conventional life-saving equipment has the following disadvantages.
1. They generally make use of a frictional brake, which gives rise to a short service life and degraded reliability. As a result, they are suitable for use by professional firemen rather than by the untrained individuals for saving themselves.
2. The descending speed of the equipment is not adjustable. The speed increases as the body weight increases. As a result, it is disadvantageous to pass through the fire and rescue children. Also, they cannot stop in the air where necessary.
3. The descending speed of the human body is affected by the resistance generated between gears and ropes disposed between them. Because the ropes are made of steel covered by twines, the ropes are not fireproof and are not safe when passing through the fire.
4. As frictions occur when the ropes pass through the gears, the ropes are easy weakened and broken, which can decrease the resistant force resulting in the faster descending speed and degraded safety.
5. They need to be maintained and repaired regularly, resulting in a high level of availability for their use.
6. The height of application is limited (generally less than 100 m).
7. When used, two ropes move relatively and therefore it is easy to hurt users.
8. They are inconvenient to use because their main body is separated from the ropes.